CN8237EBGB Mindspeed Technologies, CN8237EBGB Datasheet - Page 177

• Manufacturer Part Number: CN8237EBGB
• Description: ATM SAR 622Mbps 3.3V ABR/CBR/GFR/UBR/VBR 456-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8237EBGB

• Package: 456BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 622 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3.135 V

CN8237
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
28237-DSH-001-C
APPLICATION EXAMPLES: Tunnels
Figure 6-6, previously, shows priorities five and six used as CBR tunnels for UBR and VBR traffic.
The host assigns a fixed number of Schedule table slots to the tunnel to reserve a fixed rate. Each
time an assigned slot is encountered by the Cell Scheduler, it selects a VCC from a round-robin queue
of active VCCs assigned to that priority.
1/100th of the CBR bandwidth assigned to the tunnel. Tunneling enables system-level end users to
purchase CBR services from a WAN service provider. The purchaser can then dynamically manage
the traffic within this leased CBR tunnel as CBR and/or a combination of other service categories.
tunnel priority five, is through a private ATM network, perhaps a corporate ATM campus backbone.
The other tunnel, priority six, carries traffic through a public network. This topology allows the end user
to lease reserved CBR bandwidth from an administrative domain, but manage the usage of the tunnel
in an arbitrary fashion.
real-time VBR, the next highest priority to non-real-time VBR, the third highest priority to ABR, and the
lowest priority to UBR. This in effect establishes four multi-service pipes, each on equal priority to the
others (since the scheduler services each of the four pipes equally). Thus, the 4 rt-VBR priorities have
effectively the same priority, and so on through the four levels of priority serviced in each pipe.
number of VBR/ABR priorities is 12. CBR_TUN = 1, SLOT_DEPTH = 110.
4 separate tunnels or pipes. Each can have an equal 1/4 share of the bandwidth available to the port by
provisioning every fourth schedule table slot to one tunnel for each of the four tunnels.
Figure 6-11 illustrates a different use of CBR tunnels. In this example, the user has established
In each of the tunnels, 4 priority levels are assigned. The highest priority in each tunnel is assigned to
Highest VBR/ABR Scheduling priority is 15 (that is, PRI=15). Thus, VBR_OFFSET = 3.
For example, 100 UBR VCCs with PRI = 6 might currently be segmenting data. Each will get
In this example, the user has configured the CN8237 to manage two independent tunnels. The first
Mindspeed Technologies
™
6.2 xBR Cell Scheduler Functional Description
6.0 Traffic Management
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